" […] the caller might say abruptly, 'Whoozis?' In that case I would say grandly, '*Whom* are you calling, sir?' And he would hang up immediately without even an expletive. Of all the four-letter words I know, the speediest turn-off in such circumstances is *whom*. "
― Lilian Jackson Braun , The Cat Who Talked to Ghosts (Cat Who... #10)